The purpose of using molecular graphics, computer modeling, and sequence analysis is to gain insight into macromolecular or biological structures. Using molecular graphics, scientists can computationally construct models which may be useful in deciding between two or more alternative interpretations of biochemical or structural data. Computer modeling is often important in understanding biophysics or other biochemical relationships and how these relate to biological structures. Sequence analysis uses the one-dimensional amino acid sequence of proteins together with both Fourier analysis and other predictive algorithms to attempt to identify parts of the sequence which may have a regular structure. These interrelated computational methods are used to extrapolate known structural information to predict useful three-dimensional relationship. Often, three-dimensional structural information is unavailable or experimentally intractable. Two studies currently in progress include collaborations with PSL, DCRT to study computer models of biological or biomedical systems, and a collaboration with LSBR, NIAMS to predict the structure of macromolecules. Progress this year has included studies involving computer models of biopolymers, which have yielded information on the migration of photons in nonuniform media, and reaction related diffusion phenomenon, resulting in two publications. The first study has been extended to evaluate the detection of inclusions hidden in tissue using photons, and has been submitted for publication.